Quiz: 5 Skin Signs of Spring

April 21, 2017

The signs are everywhere. See if you recognize these 5 skin eruptions often seen when man gets back to nature.

As spring temperatures rise in many parts of the country, outdoor activity is more and more inviting. But when man heads back in to nature, the reunion may come with a sting, or a bite, or a rash.

Following are 5 images of skin lesions related to different types of outdoor activities many of your patients may be ready to resume. Can you identify them?

Case 1. In early summer, an 8-year-old boy living in rural central Virginia was seen for evaluation of a rash on his buttock that had become pruritic. His father had removed a tick about 10 days earlier. The 4- x 2-cm lesion had 2 central papules with an outer ring in a figure-8 pattern (Top), consistent with 2 bites and 2 primary lesions, and appeared to be consistent with erythema migrans. Early localized Lyme diseae was diagnosed. However, the removed tick (Bottom) had a white spot on its dorsum, characteristic of Amblyomma americanum, or the Lone Star tick. Based on knowledge of the vector, what was the revised diagnosis?


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Answer:Southern tick-associated rash illness (STARI)

This tick is not generally considered to be a vector for Borrelia burgdorferi, the spirochete responsible for Lyme disease, but it has been implicated as a cause of STARI, also called Lyme-like illness, southern Lyme disease. Patients with STARI may present with fever, headache, fatigue, and muscle and joint pains, although they tend to be less symptomatic and recover more quickly than patients with Lyme disease.



Question 2. A 55-year-old truck driver in the rural Midwest was hospitalized with fever, headache, poor appetite, a blanching rash, and diffuse pain. Small red spots on his forearms and legs later spread to his trunk, palms, and soles. He suspected poison ivy exposure in the woods behind his home. His wife had found a brown tick in his umbilicus a week earlier. Does the distribution of the rash suggest a diagnosis to you? 

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Answer: Rocky Mountain spotted fever

This history--known tick bite followed by fever, myalgia, arthralgia, and diffuse peripheral rash-- strongly suggested Rocky Mountain spotted fever, the most frequently reported rickettsial disease in the United States. Most cases occur between April and September, the period associated with increased numbers of adult and nymphal ticks. The patient's initial RMSF titer was 1:64, borderline positive for RMSF; at follow-up 3 months later, the Rickettsia rickettsii titer was 1:512 (normal, less than 1:32).



Question 3. An 11-year-old boy presented for evaluation of an erythematous, pruritic, papular rash that developed several days after swimming in a Wisconsin lake. He was otherwise completely healthy. There is a clue to diagnosis of the rash in the location of his recreation. What is it?

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Answer: Cercarial dermatitis (swimmer's itch)

The boy had cercarial dermatitis (swimmer’s itch), a hypersensitivity reaction that occurs after exposure to schistosome larvae in freshwater lakes. Outbreaks are most common in the Great Lakes region of the United States but occur during summer months throughout the world. Several days to 2 weeks after initial exposure, a mild to moderately pruritic, erythematous, papular, sometimes pustular eruption develops on any skin that had been exposed to infested water. In sensitized persons, the eruption develops within hours of exposure.



Question 4. The asymptomatic white spots on the arms of a 46-year-old woman have been present for 2 years. She enjoys gardening and other outdoor activities but is concerned that the lesions are related to sun exposure. The patient has taken hormone replacement therapy for the past 3 years. What is the most likely cause?

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Answer: Guttate hypomelanosis

Guttate hypomelanosis, attributable to long-term sun exposure, is seen frequently on the forearms and shins of women older than 40 years. It is differentiated from the depigmentation that is characteristic of vitiligo, which has a predilection for periorifacial and genital areas. Tinea versicolor, which is associated with scale, usually arises on the trunk. Some healed factitial lesions feature depigmentation caused by scarring, which was absent on this patient. Cutaneous drug reactions usually are more diffuse than this patient’s rash; hormone replacement agents, also a possible suspect, are not photosensitizing.



Question 5. Three weeks after returning from a family vacation in northern California, an 8-year-old boy presented with an unusual rash on his left forearm. He indicated that he had been bitten by an unknown insect while vacationing. The site of the bite was surrounded by a gradually advancing red margin that was indicative of erythema migrans. Pending results of serologic testing for Lyme disease, he was treated empirically with a 1-month course of amoxicillin.  Does the presumptive diagnosis of Lyme disease make sense given the geography of the boy’s vacation?

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Answer: Yes; Lyme disease has been reported in California.

The first case of Lyme disease in California was reported in 1987, and surveillance of the disease in the state began in 1989. The incidence of Lyme disease in the state is low. For 2006, it was 0.2 per 100,000 persons, compared with 56.6 cases per 100,000 persons in Delaware (seconded by Connecticut, where the annual incidence in 2006 was 51.0 cases per 100,000 persons).1

Tick-borne illnesses occur most commonly in the late spring and summer months. The characteristic rash of Lyme disease, erythema migrans, often has a bull’s-eye appearance. Erythema migrans is seen in about 80% of patients with Lyme disease.